In recent years, optical disc player devices have become widely popular for general household use, and the devices provide high image and sound qualities, have highly interactive features, and replay optical discs in which large amounts of information are recorded.
Representative high-capacity optical discs include Blu-ray disc (BD; hereinafter, referred to as “BD”). BDs offer high data storage capacity; single layer discs contain 25 gigabytes (GB), and dual layer BDs contain 50 GB, so that data having the image quality of high-definition movie content can be stored in the BDs. Packaged software for purchase and rent that uses the BDs is provided in the read-only media, BD-ROMs, which are manufactured with data thereon and not writable and rewritable.
Two specifications of HDMV and BD-J modes are formulated for the BD-ROM. The HDMV mode has an extended video/audio codec specification compared with that in the conventional DVD-ROM. In the specification of the HDMV mode, a high-definition image and high-quality audio are available. Because a content specification is the same as that in the DVD-ROM and a method for controlling HDMV titles is an extension of that in the conventional DVD-ROM, if content information being played is stored, a playback resuming function for DVD-ROMs may be easily provided.
The BD-J mode, having the features of the HDMV mode, can add visual representations; for example, images may be superimposed on each other with a Java® application. Menu display and video playback of BD-J titles are controlled by a Java program on a BD-ROM, so that flexible processing is enabled as compared with HDMV titles. Thus, large amounts of information are required to be stored in order to include a playback resuming function, but such information storing is impracticable for a system incorporated in vehicles.
Now, an operation for playing a BD-ROM on a disc player device will be described.
A BD-ROM, such as packaged software, has a plurality of reproducible titles and is managed for each title. They include a title that is played after power-on and before a main part is reproduced and a menu is displayed. Hereinafter, this title will be referred to as the first play. First plays include presentation of other packaged software, a preview of a movie, or demonstration content of a sound field reproduction technology. Some packages have first plays, the reproduction time periods of which are as long as five minutes if the first plays are reproduced at a speed of 1×.
Also, in titles including a first play, the execution of the user operations may be limited by a user operation mask. The user operation mask refers to execution limitation of the user operations such as a button operation on a menu screen, menu moving, title skipping, playback stopping, chapter selecting, fast-forwarding, and fast-reversing, used by the user watching packaged software.
If the user operation mask is set, when the execution of masked user operations is attempted, a software module that deals with the user operations limits the execution thereof. The function allows for providing an operation intended by a content provider.
Thus, when a user desires to play main part video on a home Blu-ray Disc player device as soon as possible upon inserting a disc, if the user operation mask is not set in a first play, the user can reduce a first play time period by operating a remote control to execute the user operations such as menu moving, title skipping, and fast-forwarding.
Further, it has been proposed to, if a BD-ROM player device is used in an automobile, reproduce a digital stream recorded in a recording medium such as an optical disc by an operation without a GUI, like a CD player device (e.g., see Patent Literature 1).
However, in a large number of cases where disc player devices are used in automobiles, drivers are prohibited from operating their disc player devices while the vehicles are moving, so that a first play reproduction time period cannot be reduced by an operation using a remote control or a touch panel.
In particular, when the playing of a BD-J title is resumed after an engine stop or an instantaneous power interruption, impracticably, high-capacity memory is required to carry out continuation playing (playback resuming). For this reason, typically, in the foregoing cases, the content is played from the first play again. For example, if a user on a drive stops the engine to take a rest and restarts the engine after the rest, the same first play is reproduced for minutes every time, and then main part video is played.
In view of such circumstances, an optical disc device has been proposed which automatically shortens a first play in reproduction to allow for reducing a time that elapses before menu display or main part playback in an environment where the device is often powered on and off (Patent Literature 2).